Vapor phase preparation of fluorided solid oxides

Abstract

Methods for the vapor phase preparation of fluorided solid oxide activator-supports, using certain calcining temperatures and fluoriding temperatures, are disclosed.

We claim: 
     
       1. A process to produce a fluorided solid oxide, the process comprising:
 (a) calcining a solid oxide at a peak calcining temperature to produce a calcined solid oxide; and 
 (b) contacting the calcined solid oxide at a peak fluoriding temperature with a vapor comprising a fluorine-containing compound to produce the fluorided solid oxide; 
 wherein the peak fluoriding temperature is at least about 50° C. less than the peak calcining temperature, and 
 wherein the surface area of the fluorided solid oxide produced by the process is at least about 5% greater than a surface area of a fluorided solid oxide obtained by performing the contacting step at the peak calcining temperature. 
 
     
     
       2. The process of  claim 1 , wherein:
 the peak calcining temperature is in a range from about 500° C. to about 1000° C.; 
 the peak fluoriding temperature is in a range from about 350° C. to about 650° C.; 
 the peak fluoriding temperature is from about 60° C. to about 600° C. less than the peak calcining temperature; or 
 any combination thereof. 
 
     
     
       3. The process of  claim 1 , wherein:
 the peak calcining temperature is in a range from about 600° C. to about 750° C.; 
 the peak fluoriding temperature is in a range from about 400° C. to about 600° C.; 
 the peak fluoriding temperature is from about 75° C. to about 400° C. less than the peak calcining temperature; or 
 any combination thereof. 
 
     
     
       4. The process of  claim 1 , wherein:
 the fluorine-containing compound comprises perfluorohexane, perfluoroacetic anhydride, tetrafluoroethane, or a combination thereof; and/or 
 the fluorided solid oxide comprises fluorided alumina, fluorided silica-alumina, fluorided silica-zirconia, fluorided silica-titania, fluorided silica-coated alumina, or a combination thereof. 
 
     
     
       5. The process of  claim 1 , wherein the fluorine-containing compound comprises a fluorocarbon. 
     
     
       6. The process of  claim 1 , wherein the solid oxide comprises silica, alumina, titania, zirconia, magnesia, boria, silica-alumina, silica-coated alumina, silica-titania, silica-zirconia, alumina-boria, or any combination thereof. 
     
     
       7. The process of  claim 6 , wherein the fluorided solid oxide comprises fluorided silica-alumina, fluorided silica-coated alumina, fluorided alumina, or a combination thereof. 
     
     
       8. The process of  claim 1 , wherein step (a) and step (b) are performed in an oxidizing atmosphere. 
     
     
       9. The process of  claim 1 , wherein:
 the fluorided solid oxide comprises from about 5 to about 12 wt. % fluorine, based on the weight of the fluorided solid oxide; and/or 
 the vapor comprises from about 100 ppmv to about 20 volume % fluorine-containing compound. 
 
     
     
       10. The process of  claim 1 , wherein:
 the contacting in step (b) is performed for a time period of less than about 8 hr; and 
 the fluorine-containing compound is present in the vapor for less than about 15 min. 
 
     
     
       11. The process of  claim 1 , wherein the fluorided solid oxide has:
 a pore volume in a range from about 1.2 to about 2 mL/g; and 
 a surface area in a range from about 275 to about 700 m 2 /g. 
 
     
     
       12. The process of  claim 1 , wherein the catalyst activity of a catalyst system containing the fluorided solid oxide produced by the process is at least about 5% greater than that of a catalyst system containing a fluorided solid oxide obtained by performing the contacting step at the peak calcining temperature. 
     
     
       13. A fluorided solid oxide produced by the process of  claim 1 . 
     
     
       14. A catalyst composition comprising a transition metal compound and the fluorided solid oxide of  claim 13 . 
     
     
       15. A polymerization process comprising contacting the catalyst composition of  claim 14  with an olefin monomer and optionally an olefin comonomer under polymerization conditions to produce an olefin polymer. 
     
     
       16. A process to produce a fluorided solid oxide, the process comprising:
 (a) calcining a solid oxide at a peak calcining temperature in an oxidizing atmosphere to produce a calcined solid oxide; and 
 (b) contacting the calcined solid oxide at a peak fluoriding temperature with a vapor comprising a fluorine-containing compound and oxygen to produce the fluorided solid oxide; 
 wherein the peak fluoriding temperature is from about 50° C. to about 600° C. less than the peak calcining temperature, and 
 wherein the surface area of the fluorided solid oxide produced by the process is at least about 5% greater than a surface area of a fluorided solid oxide obtained by performing the contacting step at the peak calcining temperature. 
 
     
     
       17. The process of  claim 16 , wherein:
 the peak calcining temperature is in a range from about 550° C. to about 900° C.; 
 the peak fluoriding temperature is in a range from about 350° C. to about 650° C.; and 
 the peak fluoriding temperature is from about 75° C. to about 300° C. less than the peak calcining temperature. 
 
     
     
       18. The process of  claim 16 , wherein:
 the fluorine-containing compound comprises perfluorohexane, perfluoroacetic anhydride, tetrafluoroethane, or a combination thereof; and 
 the fluorided solid oxide comprises fluorided silica-alumina, fluorided silica-coated alumina, fluorided alumina, or a combination thereof. 
 
     
     
       19. The process of  claim 16 , wherein:
 the surface area of the fluorided solid oxide produced by the process is from about 5% to about 15% greater than a surface area of a fluorided solid oxide obtained by performing the contacting step at the peak calcining temperature; and 
 the catalyst activity of a catalyst system containing the fluorided solid oxide produced by the process is at least about 10% greater than that of a catalyst system containing a fluorided solid oxide obtained by performing the contacting step at the peak calcining temperature.